/Engine/Source/Runtime/Engine/Classes/GameFramework/Character.h
Find usable root motion replicated move from our buffer. Goes through the buffer back in time, to find the first move that clears 'CanUseRootMotionRepMove' below. Returns index of that move or INDEX_NONE otherwise.
int32 FindRootMotionRepMove ( const [FAnimMontageInstance](API\Runtime\Engine\Animation\FAnimMontageInstance) & ClientMontageInstance ) const